写在init()方法；

个人觉得在navigation的代理方法里。

- (void)navigationController:(UINavigationController *)navigationController willShowViewController:(UIViewController *)viewController animated:(BOOL)animated {
     首先获取程序的主窗口
     UIWindow *keyWindow = [UIApplication sharedApplication].keyWindow
     //获取tabBarVC
      UITabeBarController *tabBarVC = (UITabBarController*)keyWindow.rootViewController;
     //移除系统的tabBarButton
     for(UIView *tabBarButton in tabBarVC.tabBar.subviews) {
          if ([tabBarButton isKindOfClass:NSClassFromString(@“UITabBarButton”)]){
               [tabBarButton removeFromSuperview];
          }
     }
}

应该写在layoutsubviews 里面

我也是在 nav 里面做这件事

- (void)pushViewController:(UIViewController *)viewController animated:(BOOL)animated
{
    if (self.childViewControllers.count >= 1) {
        viewController.hidesBottomBarWhenPushed = YES;
    }

    [super pushViewController:viewController animated:animated];
}

CocoaTouch 在一个NavigationController进行Push操作的时候，隐藏TabBar的方式，应该是调用的sendSubviewToBack这个方法把TabBar给放到后面去。我在自定义转场动画时，通过这种方式做到和苹果默认的一样的效果。你可以试试。

let needPushTabBar = toVC.navigationController?.tabBarController != nil && toVC.hidesBottomBarWhenPushed && toVC.navigationController?.childViewControllers.count == 2
        
        if needPushTabBar {
            toVC.navigationController?.tabBarController?.view.sendSubviewToBack(tabBar!)
        }

/**
 *  重写push方法实现界面跳转后的各种设置
 */
- (void)pushViewController:(UIViewController *)viewController animated:(BOOL)animated{
    if (self.childViewControllers.count > 0) {
        // push跳转后隐藏底部TabBar栏
        viewController.hidesBottomBarWhenPushed = YES;
    }
    
    // 先设置属性,再调用super的push方法,避免设置的属性被覆盖
    [super pushViewController:viewController animated:animated];
}